08 Club Car DS Solenoid Replacement

[Margaritaville]

Hello. I appreciate your expertise.

I have a Club Car DS 48v. It’s an IQ (shunt/ Sepex).

I bought it used. It has a plumb quick bandit motor. Besides that, all looks stock except the solenoid and controller cables look upgraded to 4awg.

I recently upgraded the cabling all around and now I’m upgrading the solenoid (Curtis sw180).

The stock solenoid in place now does NOT have a resistor or diode.

With the shunt motor do I need a diode or resistor? Or does the controller take care of it.

By the way, I have. Navitas 600amp controller on order.

I appreciate your help. Mike.

[Margaritaville]

Here is what I learned. Not news to many of you, but posting for the benefit Of the next guy. I can’t take credit. This from an email from some far more knowledgeable.

Back in the day, the early generation of controllers required the diode and pre-charge resistor to because it was a hold over from the days when forklift controllers were used. When golf carts first got their controllers, they were a series motor and controller that literally came out of a forklift. Those controllers needed the diode and the pre-charge resistor because the controllers at the time were pretty simple and didn't have much in functionality. Series controllers don't control the solenoid, so a method to protect the interlock switches in the wiring diagram was needed to deal with the inductive voltage spike that would happen when the solenoid opened. The diode caps that voltage spike to a more manageable level. The pre-charge circuit was needed because the controller didn't turn on until the operator stepped on the throttle. In order to keep the solenoid contacts from welding, they put in the resistor to charge the capacitors by basically backfeeding the controller through the B+ terminal.


In the recent years as the industry shifted to the Shunt wound motor, that motor design gave them a ton more options for functionality. One of those functions was the anti-roll away feature. Because the controller could be powered up in a type of standby mode, so as to be able to slow the cart if it started moving, it gave the controller and cart engineers the ability to move the controller pre-charging to in the controller through the tow/run switch. As part of the anti-roll away functionality, the controller now needed to be able to open and close the solenoid as needed. This allowed the diode to be put internal to the controller to deal with those spikes.

As technology moved on so did where things were placed in the cart.

So when you look at our documentation, you'll see the diode is needed on the Series carts but not the shunt wound carts. Again this is just the limits of the technology, the series carts the controller doesn't control the solenoid, so it needs the diode. The pre-charge resistor is not needed on any of the carts because we can compensate for that with the design of the adapters we use on the series vehicles.

In some of the videos, you might see a resistor being hooked up to the solenoid. Those are going to be on the AC carts and is not a pre-charge resistor, that is a bleed resistor to protect the battery pack from damage in the situation when your battery pack is full and the cart is regen'ing. There is no where for the energy to go if the batteries are full, so it shunted through the resistor to bleed that energy off until regen stops or there is room in the battery for accepting a charge.

[simicrintz]

Quite possibly a stupid question (I am good at those!), but would there be any downside to leaving the diode in no matter which system you have? I am just thinking that it may just be one small bit of insurance of juice flowing back without the diode (but most likely not needed).